Agreed ... so why is there such a huge, overwhelming amount of paranoid, unreasoning hostility directed at FOSS coming from Microsoft and its supporters?

Because FOSS is an ideology that not everyone subscribes to? Because it threatens existing businesses that have invested vast amounts of money into products, only to see FOSS equivalents springing up and undercutting them? Large companies generally don't like change, and open source is a much more serious threat than mere commercial competition.

"Agreed ... so why is there such a huge, overwhelming amount of paranoid, unreasoning hostility directed at FOSS coming from Microsoft and its supporters?

Because FOSS is an ideology that not everyone subscribes to? Because it threatens existing businesses that have invested vast amounts of money into products, only to see FOSS equivalents springing up and undercutting them? Large companies generally don't like change, and open source is a much more serious threat than mere commercial competition. "

OK. At least this identifies where the "hate" problem stems from. Big companies who want to charge people a fortune for a given service or product absloutely hate it when the people get it for themselves.

"Ideology"? Wow, that gives it fat too much credit. It's a development methodology. That's all.
"

Free Software is an ideology. Open Source is a development methodology. FOSS (Free and Open Source Software) is referring to software created as a result of the Open Source development methodology by people who may or may not subscribe to the Free Software ideology.

Now, many non-Free Software, Open Source developers (such as Linus) have the ideology that Open Source is the best - if not only - methodology which should be used to create software, but that's an ideology about Open Source rather than Open Source itself actually being an ideology.

In any case, talking about ideology and FOSS isn't entirely incorrect because the Free Software side of things is indeed an ideology, but it confuses things because Open Source is, as you say, a development methodology.